FIG. 1 is a diagram of picturing the relationship between the driving voltage and the brightness of an OLED. When an OLED in a panel is applied with a forward voltage higher than a turn-on voltage Von which depends on the panel process, it is turned on and the higher the driving voltage is, the brighter the OLED will be. If the driving voltage is lower than the turn-on voltage Von, either a forward voltage or a backward voltage, the OLED is dark. However, the OLED controller's cost depends on the wafer process. A higher voltage process will have a higher cost.
For more detail, FIG. 2 shows a conventional driving arrangement for an OLED panel, in which power supply 210 may provide a wafer process voltage Vpcs, a microcontroller operation voltage Vmcu, and a ground voltage Vgnd for gate driver 220 and source driver 230. The gate driver 220 and the source driver 230 are connected to each other by several synchronous control signal lines 250, and under the control of controller 260, produce gate signals and source signals to drive OLED panel 240. The gate driver 220 has a high-voltage terminal (Vgh) 222, a low operation voltage terminal (Vdd) 224, and a ground terminal (GND) 226 to receive the voltages Vpcs, Vmcu and Vgnd, respectively, and the source driver 230 has a high-voltage terminal (Vsh) 232, a low operation voltage terminal (Vdd) 234, and a ground terminal (GND) 236 to receive the voltages Vpcs, Vmcu and Vgnd, respectively. Since both the ground terminals 226 and 236 receive zero voltage, i.e. Vgnd=0V, the voltages of the gate driver 220 and the source driver 230 are the same level, and for the OLEDS, the maximum operation voltage, the voltage difference between the voltages of the terminals 232 and 226, is same as the wafer process voltage, which equals to Vpcs and can not be adjusted based on user's requirement. Otherwise, in order to drive the OLED panel 240 to be brighter to thereby have a better displaying quality, it is needed to replace the gate driver 220 and the source driver 230 to provide higher Vpcs to thereby increase the driving voltage for the OLED panel 240, and it increases the cost at the same time.
Therefore, the present invention proposes a driving arrangement which can provide a higher driving voltage than the controller's wafer process voltage to drive an OLED panel.